Aircraft back-turret cupola



June 6, 1944. LANCIANI AIRCRAFT BACK-TURRET'CUPOLA Filed Sept. 20, 19407- TORE l mvc m/v/ BY \QW' ATTORNEYS.

Patented June 6, 1944 AIRCRAFT BACK-TURRET CUPOLA Ettore Lanciani,Milan, Italy; vested in the Alien Property Custodian ApplicationSeptember 20, 1940, Serial No. 357,514 In Italy September 25, 1939 3LClaims. (CI. 89-36) This invention is a novel aircraft back turretcupola, in the nature of a top enclosure or hood placed protectivelyabove the rear gun turret of any type of aircraft, the combined turretand hood being adapted to enclose a machine gun or other firearm, aswell as the gunner or operator thereof. The novel features of theinvention may be disclosed without the need of illustrating theaircraft, or fuselage; and for that matter the gun turret itself neednot be disclosed, except by reference to an illustrative gun'turretadequately shown in this applicant's copending application filedDecember 16, 1939, Serial No. 309,569 directed to Armed rotating turretsfor aircraft, Fig. 1 of which in particular well shows such a gunturret, and machine gun, with a general indication of a covering hood orcupola protectively extending above the space accommodating the gun andgunner; the turret illustrated in the copending application being of therevoluble type so that, notwithstanding that the turret may be locatednear the rear of the aircraft, the gun may be swung leftward orrightward to a certain extent in aiming or following the target, whilenaturally the gun and mechanism also are trunnioned for upward anddownward swing to adjust the firing elevation.

The general object of the present invention is to afford, especially forthe rear gun turret for aircraft, a construction or physical shapingsuch as to afford important operational advantages. One such advantageis to afford superior visibility for the gunner. Another advantagerelates to the matter of the relative wind, or rearward air flow aboutthe aircraft, and has to do with the minimizing of the resistance of theturret and cupola to the wind, and the minimizing of eddies near therear or tail side of the combined turret and cupola. Other advantageswill appear from the hereinafter following description of anillustrative example of the invention.

In the accompanying drawing, Fig. 1 is a top plan view of a turretcupola or hood adapted to serve as a top covering for a revoluble gunturret such as shown in said application No. 309,569; this figurecontaining the direction arrow T to indicate the forward direction oftravel of the aircraft, and the firing arrow F of the gun G, showingthat it is mounted in a rear turret for firing oppositely to thedirection of travel.

Throughout this description the line of direction of the arrows T and F,as shown, will be considered as the longitudinal direction, althoughnaturally the turret may be swung through an extent of arc, to eitherside of the longitudinal, by the rotation of the turret and coveringcupola. The circular shape of the cupola indicates its rotatablecharactenabout the vertical axis V of the turret.

Fig. 2 is a longitudinal section view taken on the section line 2-2 ofFig. 1, slightly on the near side of the longitudinal diameter.

Fig. 3 is a similar longitudinal section, taken on the line 3-3 of Fig.1, subtending a somewhat shorter chord.

Fig. 4 is a transverse sectional view taken on the section line 4-4 ofFig. 1, certain parts to the right thereof being seen in interior view.

Fig. 5 is a section taken on a. shorter chord, namely on the sectionline 5--5 of Fig. 1.

The cupola or hood thus illustrated may be considered as adapted to beset down'in covering position upon a rotatable or oscillating cupolasuch as that illustrated in said application No. 309,569, with asuificient arching or crowning of the covering cupola to accommodate themachine gun, directed rearwardly, and the gunner facing rearwardly,usually with the gun at his righthand side, and the ammunition feedingmechanism at the other side of the gun. The mode of mounting the cupolaupon the turret, and its attachment there, are deemed unnecessary toindicate since the present invention is concerned not with such detailsbut with the structure and shape of the cupola itself, as will next bedescribed.

The cupola is seen to comprise a walled structure, the general portion 1of which is of generally round outline and thus adapted to be placedupon the turret to cover the enclosed gun and gunner, and such generalwall of the cupola being of generally arched, cambered or crowned shape,with its longitudinal sections generally of substantially airfoil orstreamline contour. For illustration, two such longitudinal sectionshave been illustrated in Figs. 2 and 3 where it will be seen that,except for a minor interruption to be described, the cambered shape isof airfoil or streamline contour, comprising at its front portion or endan enlarged bulbous shape 8, passing around to a peak somewhat forwardof the center, and thence with tapering away shape 9 toward the rear ortail end of the section. With the same exception, the transversesections are of generally convexly arched curvature, and preferablysubstantially symmetrical, as best shown in the diametral section viewFig. 4. The curvature of the transverse section shapes is shown asinvolving a convenient polycentric of its rear portion, preferablywithin a quadrant 7' as shown, is shaped into a reentrant recess'or wallor shield affording effective rear vision, this wall being transparentor windowed. This special structure is well illustrated in all of thefigures of the drawing, the sunk wall'portionor depression comprising,in the illustrated case, a substantially fiat or horizontal wall partI0, from the front edge of which extends a slanting wall II,' the upperedge of which isconnected or integral with the general arched wall I ofthe cupola. As'best shown in Fig. 3 the wall part II is steeply in-.clined, being shown at about 45; and it is. in the nature of awindshield, either wholly transparent, or having :a window l3 throughwhich the gunner is afiorded a clear rearward view for aiming and firingpurposes, I

In addition .to the fiat wall I0, and-the inclined wall H, the recessedshape of the cupola is bounded by a triangular upstandingwall M, seemore especially Figs. 2 and 5, thetop of which connects or merges withthe general wall portion I, and the other edges of which'are united withthe wall portions Wand II respectively. By. this shaping the entireinterior is enclosed and protented from exposure and weather.- The threewalls 10, H and M are preferably plane. 1 The following generalarrangement is preferred. The gunner sits behind the vision wall l'llooking rearwardly, at the left part of the enclosed space, while thegun'preferably is 10- V '10 depression, which breaks into but mergeswiththe arched general curvature of the cupola, and I such depressioncomprising a steeply inclined;

cated to the right of the upright wall It, and

for this :purpose the general wall or shell portion I of the cupola iscut away to form an aperture 12, in the nature of an elongated slotpermitting up-and-down swinging of the-gun in training it upon thetarget.

While the describeddepression parts of the cupola wall, which may bestruck from the general material, constitute somewhat of aninterruption, at one rear quadrantoi the streamline contour; the loss ofairfoil effect -isminimized, by the fact that'the wall I! slantsdownwardly and V rearwardly, and to some extent preserves the desiredcontour to minimize air resistance and 'eddying, as is clearly seen bycomparison of Figs.

2 and 3.

Naturally theexact constructional shape and details may be considerablyvaried without departingfrom' the principles described, and. it isnotintended to limit the invention to. the illustrative disclosure ofthe drawing.

'What is claimed isz a 1. A cupola for arr-aircraft rear gun turret,comprising awalled structure having a generally circular outlineadaptedtto be .placed over-the turretto ccverthegun and the gunner; saidcupola structure being characterized in having its wall of generallycambered shape and wherein the wall at oneiside of its rear portion isshaped into a' reentran-t depression breaking but merging with thearched general curvature of the quadrant-l of the cupola: and whereinanopening is providedain the adjacent rear quadrant through I whicha gunmay be-fired.

3. The structureset-forth in claim- 1 wherein the base of thedepression-is substantially'flat and in the plane of the. air foiltipand .thein-' clined wall makes an angle with ,the extension ofsuchplane of approximately said depres.

